The frequency and pattern of phencyclidine (PCP) use during pregnancy and its relationship to anomalies in the developing fetus are examined. Subjects include women receiving prenatal care and their newborn infants. PCP levels measured in maternal and neonatal blood and urine at birth and during the first three days postpartum are compared (fetal/maternal ratio), and the disappearance of the drug over time is determined. Physical, neurological, and behavioral abnormalities are correlated with measured drug levels and maternal drug history.